Abrasive wheel dresser



Oct. 10, 1944. RENNER ABRASIVE WHEEL DRESSER Filed April 13, 1942 2 Sheets-Sheet 1 FIG. I O

- INVENTOR HAROLD G.R NNER BY 3 ATTO Oct. 10, 1944. NNE v 2,360,Q13

ABRASIVE WHEEL DRESSER Filed April 13, 1942 2 Sheets-Sheet 2 FIG.8. FIG.9.

INVENTOR HAROLD 6.RE NER BY ATTO YS Patented Oct. 10, 1944 UNITED STATES PATENT OFFICE 2360,013 .A'BRASIVE immsslm Harold George 'RennenDetroit, Mich.

Application April 13, 1942,:SerialI-No.438,776-

8 Claims.

This invention relates todevices for-dressing abrasive wheels and the like tosubstantiallyany desired-contour, and has for one of. its principal objects the *provision of a tool that will enable the ready formation 'of'various arcs on the wheel and also of plane surfaces, including inclined pl'anestangent to a desired arc.

Anotherobject of my invention is the mounting of a'dressing tool, such as-a cutting diamond, in a bar carried by an oscillatable cradle, with provisions for adjusting the position of the bar-to move the diamond to desired distances on opposite sides of the axis of the cradle -whereby either convex or concave arcs may be produced on the abrasive wheel at'will.

A further object of'my-invention is the arrangement of the diamond-carrying bar for independent oscillatory movement upon and relativelyt'o the cradle in any desired angular position of' the cradle, with provisions for restraining the diamond to straight line reciprocation during such oscillations of the bar, whereby plane surfaces maybe produced on the wheel at various selected angles.

A further object of 'myinvention'is the'provision of stop mechanisms wherebythe extent of the desired are or the width. of a desired "plane surface can be accurately determined and maintained.

Other objects andadvantages will be apparent to those skilled in the art from the following description, wherein reference is made to the accompanying drawings illustrating a preferred embodiment of my .invention and wherein similar reference numerals designate similar parts throughout the several'views.

In the drawings:

Fig. 1 is a plan View of my improved abrasive wheel dressing device.

Fig. '2 is a side elevational view thereof with parts-broken away.

Fig. 3 is a detail vertical cross section through the upper portion of my improved'dresser, taken substantially on the line 3-3- of Fig. 1.

Fig. 4 is a horizontal cross section taken substantially on the line 4-4 of Fig. 2 andlooking in'thedirectionof'the'arrows.

Fig. '5 is a front elevation of my improveddresser.

Fig. 6 is a detail vertical cross section taken substantially'on the line 66 of Fi 2.

Fig. '7 is a detail perspective View of the rear extremity of the cradle and the associated cross bar utilized in my improved dresser, and

Figs. 8, 9 and 10 are detail sectional views illustrating varied .cuts .and formszmade on abrasive" wheels with :my .:impr oved dresser.

Referring now :to the drawings, my improved abrasive wheel dresser is shownas mounted on asupporting frame ll formed of spaced parallel bottom members HA and upright end portions MB. This supporting frame is preferably made of steel-or cast iron, andL-maybe secured for use upon :a magnetic chuck, or .may be otherwise mnunted'on a pedestal, bracket or the like. :In th:e;erid?pieces II'B are formed bearings for trunnions :12 of a-cradle, herein shown'as-formed with a longitudinal lower member l3 connectedattits extremitiesLto end pieces l4,'pre'ferably polygonal in'aorosssection, to'form guides for vertically'adjustable L-shapedblocksl5 carrying a longitudinallylextending bar I6 in which the dressing tool 11, such asa cutting diamond, is adjustably secured, as by the set screw [8 threaded in the collar 4-9. at substantially the central portion of-the bar [6. The .trunm'onsil2 are normally arranged at-substantially the uppermost portion of the cradleand the turning axis of the-cradle is accurately located-at a desired distance above the lowermost portionof the fixed lower bar i3, so asto enable accurate micrometer measurements betweenthe lowermost portionof the cradleand the working extremity of the dressing tool 1.1.

.As .best shown. inv Fig. .6, I :have provided a vertically adjustable set screw 20 .at substantially the centralportion of the bar 13, and the lower rounded edge ofsuch set screw projects slightly below the lower surface of the bar l3for engagement with one jaw of the micrometer. I have found thatby arranging the roundededge of the setscrew 20 accurately at aknown distance, say

' 3 /2 incheS below the axis of the cradle, ample room for adjustment for practically all uses of a dressing tool isafforded, and enables .ready formation of both convex and concave arcs on the abrasive wheels by suitably adjusting the hei'ght of the dressing tool I] above or below the axis of' the cradle. Such vertical adjustment of contours of the polygonal end pieces l4, adjusting screws 53 being threaded through the straps into the blocks l5 so as to clamp such jaws in any desired adjusted position upon the end pieces M of the cradle.

In practice, the screws |5B are loosened and the blocks |-5 with the attached longitudinal diamond-carrying bar |6 are slid toward or away from the axis of the cradle to a desired new position, after which the screws |5B are turned home suificiently to clamp the blocks I5 in the new position. The polygonal shape of the end pieces and the interfitting grooves in the blocks |5 and straps |5A enable an automatic maintenance of parallel relations between the blocks l5. However, to enable checking of adjusted positions at the opposite ends of the diamond-carrying bar I6, I preferably mark space indications on side faces of the end members M of the cradle, substantially as shown at 2| on Fig. 2.

The diamond-carrying bar l6 has an oscillatory movement upon the blocks .|5, as will be hereinafter pointed out, such movement being independent of the desired radially adjusted position of the blocks l5 as well as of desired angular poe sitions of the cradle. a

Means are provided for oscillating the cradle, as for example, the handle 22, fixed at the forward extremity of one of the trunnions l2 of the cradle. The handle 22 carries a set screw 23 for locking the cradle in various angular positions, as for example, that shown in dotted lines in Fi 5.

The set screw 23 is preferably provided with a knurled head, for ready turning during the Posh tioning of the cradle, as Well as with a suitable slot for a screw driver or other instrument to enable firm anchoring of the cradle in the selected position.

The extent of the oscillations of the cradle may be controlled by suitable stops, and I have herein shown a pair of stop screws 24 adapted to be threaded in anyone of a series of tapped holes 25 spaced accurately in the face plate 26 carried by one of the end members I IB of the frame. Each screw 24 passes through the menate slot of a stop link 21, which links are of a length slightly greater than the distance between the holes 25. By this arrangement any desired distance between the holes 25 may be secured by adjusting the links 21 relatively to their set screws 24, and these screws and links may be moved at will'to' any of the several spaced holes I preferably provide a semi-circular scale 28 upon the face plate 26 and provide a sight opening 29 in the handle member 22 so that the rela-.

tive angular position of the handle member, and accordingly of the cradle, can be determined, and checked, at will.

In the formation of arcs upon the abrasive wheels, the mechanism heretofore described is sufficient. The height of the Working edge of the cutting diamond I1 is first adjusted relatively to the axis of the cradle, as for example, a distance of .01 inch above the cradle axis to form a concave are on a radius of .01, or a distance of .25 inch below the cradle .axisto secure a convex arc with a radius of .25. The extent of the arc is controlled by the swing 'of the cradle during the dressing operation, and such extent of swing may be limited by suitable positioning of the stops 21 upon the face plate 26.

When it is desired to form plane surfaces upon 4 with which it cooperates.

l the bar l6.

an abrasive wheel, I preferably utilize the mechanism now to be described:

One of the L-shaped blocks l5, as the forward block, best shown in Figs. 1 and 4, carries an elongated plate 30 which is formed on its under surface with a cam slot 30A in which is pressed 8. ball 3|, as by means of the spring-pressed plate 32, adjustably fixed on the lower surface of the diamond-carrying bar I6, as by the shouldered screw 33 extending through an aperture in the bar l6 and threaded into the'plate 32, a spring 34 being arranged to normall press the ball 3| firmly into engagement with the walls of the slot 30A. The opposite end of the bar It is forked, as best shown in Fig. 4, with the width of the longitudinal open slot 35 therein being substantially the same as the width of the end post To this end, the sides of this end piece l4 may be turned on a known radius, as for example and the width of the slot 35 formed to inch so as to ride on the curved sides of the post l4. A spring pressed plate 36 maybe arranged to firmly hold the forked end of the bar l6 against the upper surface of its L-shaped block |5 during the movementsof such bar I6 independently of the cradle. As best shown in Figs. 2 and 3, a shouldered screw 31 may extend through an aperture in the plate 36 and through the slot of the forked end of, the bar i4 and then be threaded into block |5 below the bar IS, a spring 38 being arranged between the head of the screw and the plate 36.

A handle 39 may be secured to the bar l6 adjacent the plate 30 to enable oscillations of the bar |6 whenever desired, the end of the bar I5 carrying the ball 3| swinging in the path determined by the slot 30A, while the forked opposite end of the bar l6 turns about and moves relatively to its adjacent end post l4 of the cradle. By suitably arranging the curvature of the slot 30A, the path of the working face of the dressing tool may be maintained in a straight line, so that such tool merely reciprocates back and forth during the oscillations of Such curvature of the slot-30A can be determined mathematically, but I prefer an empirical determination thereof, as by reversing. the process and enforcing the travel ofthe cutting tool I! between straight line sides of a slot while oscillating the bar l6, and marking the path traveled by the ball 3| while the straight line reciprocations of the cutting tool are being made. In use, the cradle may be swung to any desired angle, and then the diamond-cutting bar l6 oscillated relatively thereto' through the medium of the handle 39, whereby variously inclined plane surfaces may be secured at will. The extent of reciprocatory travelof the working face of the diamond may b e controlled by arranging stops 40 in the L-shaped block l5 adjacent the plate 30, as best shown in Figs. 1 and 2. Slide stops 40 are preferably arranged, to be moved into and out of the path of movement of the bar l6, as, for example; in apertures adjacent opposite sides of the block l5. These stops 4!! preferably have their inner faces spaced from the longitudinal axial plane of the cradle a distance substantially equal to one-half of the width of the bar 5. With the diamond .centrally mounted in the bar l5, such-arrangement of the stops 4|] will serve to limit one end of the line of travel of the diamond 'in,.alignment with the longitudinal axial plane of the cradle, the

. side of the bar l6 contacting one of the stops-40 when'the diamond, reaches such alignment. Accordingly inclined plane surfaces of accurately determined widths can be secured, with the extremities of one or more of the plane surfaces in any desired angular relation to other surfaces on the abrasive Wheel, as for example, with the plane surfaces tangent to the extremities of a central are formed on the abrasive wheel.

In Figs. 9 and 10, variously inclined surfaces are shown in relation to adjacent arcuate surfaces 52 on abrasive wheel 5!], while in Figs. 6 and 8, only arcuate surfaces 52 are shown, although in Fig. 8 the surfaces 52 are formed with different radii.

While the drawings herein show my improved dresser mounted with the frame portions NA in the lowermost position, attention is called to the fact that the rearmost end portion MB of the frame has its outer face formed as a plane surf-ace so that it can rest upon a magnetic chuck or the like and form the bottom suporting portion of the frame ll if it is desired to utilize the dresser in such upright position.

I am aware that the invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and I therefore desire the present embodiment to be considered in all respects as illustrative and not restrictive; reference being had to the appended claims rather than to the foregoing description to indicate the scope of the invention.

Iclaim:

1. A device for dressing abrasive wheels comprising a supporting frame, a cradle pivoted thereon having substantially parallel end pieces, blocks adjustable along said end pieces radially toward and away from the cradle axis, a bar mounted at its ends upon said blocks for swinging movement with the cradle and also for independent swinging movement relatively to the cradle, a dressing tool adjustably mounted in said bar, the combined adjustments of blocks and dressing tool serving to effect accurate positionings of the working edge of the dressing tool at substantial distances on opposite sides of the cradle axis, means for oscillating the cradle, stops adjustably mounted on the frame to limit the extent of oscillation, and means for independently oscillating said bar.

2. A device for dressing abrasive wheels as recited in claim 1 wherein the ends of said bar are maintained in contact with the upper faces of said blocks by resilient pressure means.

3. A device for dressing abrasive wheels as recited in claim 1 wherein means are provided for securing the cradle in various angular positions and said bar is mounted for oscillation independently of and relatively to said cradle, one end of said bar being pivoted upon one of said blocks and the other end of said bar swinging across the other block.

4. A device for dressing abrasive Wheels as recited in claim 1 wherein means are provided for securing the cradle in various angular positions and said bar is mounted for oscillation independently of and relatively to said cradle, while the dressing tool carried by the bar is restrained to reciprocation in a straight line, one end of said bar being formed with bifurcations straddling one of said end pieces of the cradle, and the other end of said bar swinging across the block mounted on the other end piece, the swinging end portion of said bar carrying a ball,

and its cooperating block being formed with a cam slotreceiving said ball.

5. A device for dressing abrasive wheels comprising a supporting frame, a .cradle pivoted thereon having substantially parallelend pieces, blocks adjustable .along said end pieces radially toward and away :fromthe cradle .axis, a bar mounted at its ends upon said blocks, a dressing tool adjustably mounted in said bar, the combined adjustments of blocks and dressing tool serving to effect accurate positioning-s of the working edge of the dressing tool at substantial distances on opposite sides of the cradle axis, means for oscillating the cradle, means for securing the cradle in various adjusted positions, said bar being mounted for independent oscillation relatively to said cradle with one of its ends pivoted adjacent one of said blocks and its other end arranged to swing across the other of said blocks, and a handle attached to the swinging end of said bar for oscillating the bar.

6. A device for dressing abrasive wheels comprising a supporting frame, a cradle pivoted thereon having substantially parallel end pieces, blocks adjustable along said end pieces radially toward and away from the cradle axis, a bar mounted at its ends upon said blocks, a dressing tool adjustably mounted in said bar, the combined adjustments of blocks and dressing tool serving to effect accurate positionings of the working edge of the dressing tool at substantial distances on opposite sides of the cradle axis, means for oscillating the cradle, means for securing the cradle in various adjusted positions, said bar being mounted for independent oscillation relatively to said cradle with one of its ends bifurcated and straddling one of said end pieces adjacent one block, and the other end of said bar swinging across the other block, the swinging end portion of said bar carrying a ball and its cooperating block being formed with a slot receiving said ball, resilient means arranged to hold said bar upon said blocks and said ball within the slot, and a handle attached to the bar for oscillating the bar.

7. A device for dressing abrasive wheels comprising a supporting frame, a cradle pivoted thereon having substantially parallel end pieces, blocks adjustable along said end pieces radially toward and away from the cradle axis, a bar mounted at its ends upon said blocks, a dressing tool adjustably mounted in said bar, the combined adjustments of blocks and dressing tool serving to effect accurate positionings of the Working edge of the dressing tool at substantial distances on opposite sides of the cradle axis, means for oscillating the cradle, means for securing the cradle in various adjusted positions,

said bar being mounted for independent oscillation relatively to said cradle while the dressing tool carried thereby is restrained to reciprocation in a straight line, one end of said bar being formed with an elongated slot the side walls of which engage one of said end pieces above one block, and the other end of said bar swinging across the other block, the swinging end portion of said bar carrying a ball and its cooperating block being formed with a slot receiving said ball, resilient means arranged to hold said bar upon said blocks and said ball within the slot, and a handle attached to the bar for oscillating the bar.

8. A device for dressing abrasive wheels as recited n claim 1 wherein the dressing tool carried by said bar is restrained to reciprocation in a straight line whenever said bar is being oscillated independently of the cradle, one end portion of said bar being formed with bifurcations straddling one of said end pieces of the cradle, and the other end portion of said bar swinging across the block carried by the other end piece of the cradle, the swinging end portion of said bar and its cooperating block carrying interacting cam and cam-follower members guiding the path of movement of the swinging portion of said bar so as to restrain the dressing tool to reciprocating travel in a straight line,

HAROLD GEORGE RENNER. 

